Physicists detected gravitational waves from four new black-hole mergers

Artist's rendering of two merging black holes, producing telltale gravitational wave signatures that were picked up by the LIGO/VIRGO detectors..

Enlarge / Artist’s
rendering of two merging black holes, producing telltale
gravitational wave signatures that were picked up by the LIGO/VIRGO
detectors.. (credit: Aurore
Simonnet/LIGO-Virgo Collaboration/Sonoma State University
)

At a weekend workshop in Maryland,
physicists from
the LIGO and Virgo collaboration
reported four
previously unannounced detections of
gravitational waves from merging black holes, including the
biggest-known black-hole collision to date, roughly 5 billion years
ago. That merger resulted in a new black hole that is a whopping 80
times larger than the sun.

All four are part of the first official catalog of gravitational
wave events (called the Gravitational Wave Transient Catalog, or
GWTC-1), listing all events detected to date. Their addition brings
the total number to 11. Two scientific papers on the new findings
have been posted to the arXiv preprint repository (here and here), pending
publication.


LIGO detects
gravitational waves via
laser interferometry
, using high-powered lasers to measure tiny
changes in the distance between two objects positioned kilometers
apart. (LIGO has detectors in Hanford, Washington, and in
Livingston, Louisiana. A third detector in Italy, Advanced
VIRGO
, came online in 2016.) On September 14, 2015, at 5:51am
EST, both detectors picked up signals within milliseconds of each
other for the very first time—direct evidence for two black
holes spiraling inward toward each other and merging in a massive
collision event that sent powerful shockwaves across spacetime.

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Source: FS – All – Science – News
Physicists detected gravitational waves from four new black-hole mergers